Abstract: An interferometer system comprises a light redirecting system for splitting an input light beam into two secondary light beams to respectively propagate along a first optical arm and a second optical arm, and for recombining the secondary light beams after exiting the optical arms. The interferometer system also comprises a multipass optical cell positioned at the second optical arm for effecting a predetermined optical path length within the second arm.

Abstract: A reference laser beam locked to a femtosecond optical frequency comb is modulated through a high frequency electro-optic phase modulator, and laser sidebands with equal intervals are generated. Beat frequency is performed on the sixth-order sideband and the frequency sweeping laser beam, a beat signal and a frequency sweeping signal source are down-mixed to generate a difference frequency signal, and the difference frequency signal is locked to a reference clock through a digital phase detector and a PID controller. The frequency sweeping laser beam is locked to reference laser beam with a dynamic offset frequency under the closed loop control, and sinusoidal frequency sweeping is simultaneously performed together with the frequency sweeping signal source. The locked laser beam is used for absolute distance measurement, and a distance to be measured is obtained according to the synthetic wavelength transition theory.

Abstract: The invention relates to a device, such as a digital holographic microscope, for detecting and processing a first full image of a measurement object, measured with a first offset, wherein an arrangement is provided for generating at least one further full image with at least one offset that differs from the first offset.

Abstract: System and methods are provided for characterizing an internal surface of a lens using interferometry measurements. Sphere-fitting a distorted radius determines distorted pathlengths. Ray-tracing simulates refraction at all upstream surfaces to determine a cumulative path length. A residual pathlength is scaled by the group-index and rays are propagated based on the phase-index. After aspheric surface fitting, a corrected radius is determined. To estimate a glass type for the lens, a thickness between focal planes of the lens surfaces is determined using RCM measurements. Then, for both surfaces, the surface is positioned into focus, interferometer path length matching is performed, a reference arm is translated to stationary phase point positions for three wavelengths to determine three per-color optical thicknesses, and ray-tracing is performed. A glass type is identified by minimizing an error function based on optical parameters of the lens and parameters determined from known glass types from a database.

Abstract: An all-optical ultrasonic detection device based on light-induced ultrasound and laser interference. In the device, a first laser is connected to an optical switch, the optical switch is connected to a dielectric film and a second laser generates a reference laser beam and a plurality of detection laser beams. The reference laser beam generates a first frequency-shifted reference laser beam and a plurality of second frequency-shifted reference laser beams. The first frequency-shifted reference laser beam generates a carrier signal. The detection laser beams are reflected by the dielectric film and then interfere with the second frequency-shifted reference laser beams. The interference light passes through a fourth fiber coupler and reaches a second photodiode to generate a frequency-modulated signal. The frequency-modulated signal and the carrier signal are input to a frequency mixer to generate a mixed signal. An acquisition unit is configured to obtain a vibration signal for the to-be-detected object.

Abstract: Systems and methods are provided to reduce at least one differential harmonics of a resonance tracking modulation in a resonant fiber optic gyroscope (RFOG). The fundamental frequency of the resonance tracking modulation of each of the clockwise and counter clockwise optical signals is substantially identical; however, the amplitude and phase of the Nth harmonic of a clockwise (CW) resonance tracking modulation and the Nth harmonic of a clockwise (CCW) resonance tracking modulation may differ due to non-linearities in the RFOG. Embodiments of the invention diminish, e.g., reduce to zero such vectoral difference. Differential harmonics may be generated at one or more harmonics.

Abstract: An optical system includes a light source, a target device, an image detector, and an autocollimator that receives a beam of electromagnetic radiation from the light source, directs the beam to the target device, and directs the beam to the image detector. The autocollimator includes a first polarizing beam splitter that directs the beam to the target device and receives the beam reflected off of the target device, a second polarizing beam splitter that receives the beam from the first polarizing beam splitter, directs the beam to a diffraction grating device, returns diffracted electromagnetic radiation from the diffraction grating device to an array of detectors, and directs the diffractive electromagnetic radiation, a camera that measures an interference pattern of diffracted electromagnetic radiation from the second polarizing beam splitter and captures an image, and a lens assembly that focuses electromagnetic radiation from the target device to the diffraction grating device.

Abstract: Systems and methods for dynamic optical interferometer locking using entangled photons are provided. In certain embodiments, a system includes an optical source for generating a pair of photons. Also, the system includes first and second emitter/receivers that emit first and second photons towards first and second remote reflectors and receive reflected first and second photons along first and second optical paths. Additionally, the system includes a mode combiner for combining the reflected first photon and second photon into a first and second output port. Moreover, the system includes a coarse adjuster that performs coarse adjustments and a fine adjuster that performs fine adjustments to the first and second optical paths. Further, the system includes a plurality of photodetectors that detect photons from the first and second output ports. Additionally, the system includes a processor that controls the coarse and fine adjustments based on received signals from the photodetectors.

Abstract: Systems and methods are provided for performing OCT vibrography based on the synchronization of components of the OCT vibrography system. An A-scan trigger is employed to synchronize the operation of the scanning subsystem that scans the sample beam and an acoustic stimulus source that generates an acoustic stimulus for vibrographic measurements. The acoustic stimulus source is controlled such that when the scanning subsystem dwells on an imaging line selected for vibrography measurements, the acoustic stimulus is generated over a plurality of A-scans and the phase of the acoustic stimulus is locked to the A-scan trigger, such that the phase of the acoustic stimulus is incrementally modified with each A-scan. The accumulation of the acoustic phase is therefore synchronized to the A-scan trigger. The synchronization, providing synchronized acoustic phase evolution during each acoustic phase waveform cycle, permits the use of the OCT vibrography system for simultaneous anatomical and functional imaging.

Abstract: A tomographic imaging device includes a light source, a light pulse generator, a wave shaper, a splitter, a frequency shifter, a light path length changer, an optical detector, filters, a demodulator and an analyzer. The light pulse generator generates an optical pulse train from an output of the light source. The wave shaper modulates the optical pulse train by binary phase shift keying with PN codes. The splitter splits the pulse train into two signals, one is shifted by the frequency shifter, and one has a path length changed by the light path length changer. The optical detector inputs back scattered light from an object and the signal whose length has changed, and generates a difference signal. The filters filter the difference signals, and the demodulator demodulates the filter outputs. The analyzer calculates a reflection site of the measurement object by analyzing the output signal of the demodulator.

Abstract: Optical coherent receiver arrays are described. The optical coherent receiver arrays include an integrated array of photodetectors separated by integrated mirrors which may cause interference of received free space optical and local oscillator signals. The mirrors may serve as splitters, helping to align the received signal and local oscillator to cause interference. The photodetectors of the optical coherent receiver array may be electrically coupled in various manners to read out the signals. The optical coherent receiver array may be implemented in an optical coherence tomography (OCT) imaging system in some embodiments.

Abstract: Devices and methods employing stationary homodyne interferometry to aid in the determination of the magnitude and polarity of electrophoretic mobility and zeta potential of particles are provided. The devices use an optical quadrature interferometer having a sample holder loadable with an electrophoresis sample chamber that may contain sample particles undergoing electrophoresis, the optical quadrature interferometer being configured to perform optical velocimetry on the particles and to generate a quadrature signal comprising characteristics related to the speeds and directions of the particles. The quadrature signal may be used to determine the speeds and directions of particles. The speeds and directions of particles may be used, together with other information, for the determination of the magnitudes and polarities of the electrophoretic mobility and zeta potential of the particles. Constraints on vibration, light source coherence length, and measurement resolution may be relaxed.

Abstract: Described are an apparatus and a method for manufacturing a three-dimensional body comprising mutually oriented devices. In accordance with the invention, a substrate having a first and a second substrate region is provided. A first device is provided in the first substrate region. A second device is provided in the first or in the second substrate region. The substrate is bent along at least one bending edge in order to obtain a three-dimensional body. In accordance with the invention, the first device and the second device are oriented to each other by the bending in order to provide a communications path between the same.

Abstract: The present disclosure provides an OCT imaging system to reduce or eliminate frequency-domain aliasing artifacts. The frequency is shifted using a carrier frequency to define a sampling range substantially centered on the carrier frequency. An image of the sample is generated from a displayed imaging range that consists of a subset of the frequencies within the sampling range. Furthermore, the system may be configured to determine the carrier frequency such that a Nyquist frequency corresponding to the shifted frequency is extended beyond either an upper or a lower bound of an OCT quality envelope corresponding to the first portion of light. Additionally, the carrier frequency may be determined such that a lower bound of the OCT quality envelope is greater or less than a zero-frequency DC limit.

Abstract: One or more devices, systems, methods and storage mediums for optical imaging medical devices, such as, but not limited to, Optical Coherence Tomography (OCT), single mode OCT, and/or multi-modal OCT apparatuses and systems, and methods and storage mediums for use with same, for performing automated polarization control, polarization diversity and/or balanced detection are provided herein. One or more embodiments may achieve polarization diversity and balanced detection (or photo-detection) under any imaging circumstances. One or more embodiments, may achieve polarization control functionality regardless of whether such control is automatic or manual. Additionally, one or more embodiments may achieve automated polarization control, may achieve balanced detection (or photo-detection), and/or may address potential disturbances, such as, but not limited to, polarization drift over time, temperature and/or mechanical perturbations or variations.

Abstract: An optical refraction barometer measures pressure based on refractivity changes and includes: an optical light source; an optical frequency controller; a first optical phase controller; a first polarization controller; an electronic reference arm in optical communication with the first polarization controller; a second optical phase controller in optical communication with the optical frequency controller; a second polarization controller in optical communication with the second optical phase controller; an electronic sample arm in optical communication with the second polarization controller and in electrical communication with the second optical phase controller; a second sideband frequency generator; a mixer in electrical communication with the detector and the second sideband frequency generator; and a first sideband frequency generator in electrical communication with the mixer; and a dual fixed length optical cavity refractometer.

Abstract: The disclosure discloses a phase delay extraction and compensation method in a PGC phase demodulation technology. The sinusoidal phase modulation interference signal is converted into a digital interference signal by an analog-to-digital converter after amplification and filtering, and the digital interference signal is subjected to orthogonal downmixing of first-order, second-order, and fourth-order harmonics simultaneously to obtain three pairs of orthogonal harmonic amplitude signals.

Abstract: Single-shot, adaptive metrology of rotationally variant optical surfaces, such as toroids, off-axis conies and freeform surfaces. An adaptive interferometric null test uses a high definition liquid crystal phase-only spatial light modulator (SLM) as the reconfigurable null element, on which a simulated nulling phase function is encoded, based on the specifications of the surface under test to generate a null interferogram. The power component of the surface sag is nulled by system design, not the SLM, enabling the SLM to fully compensate the residual departure without the need to tilt the optic or use a custom Offner-null. By wrapping the phase function at multiples of 2*pi radian, the upper limit in sag of the optic under test is theoretically removed.

Abstract: A system and method for surface inspection of an object using optical coherence tomography (OCT) is provided. The method includes determining a first working distance; determining a first depth of field, based on the first working distance; changing the depth of field to the first depth of field; performing an A-scan of the object; moving the object; determining a subsequent working distance; determining whether the object is in focus at the subsequent working distance, if the object is not in focus: determining a subsequent depth of field based on the subsequent working distance; changing the depth of field to the first depth of field; and performing an A-scan of the object; and otherwise, performing an A-scan of the object.

Abstract: Systems and methods for evaluating critical dimensions of a semiconductor device are provided. An exemplary system includes at least one processor and at least one memory storing instructions. The instructions, when executed by the at least one processor, cause the at least one processor to perform operations. The operations include receiving information of a first set of overlay markings on a first layer of the semiconductor device and information of a second set of overlay markings on a second layer of the semiconductor device. The first layer is lower than the second layer. The operations also include receiving a plurality of diffraction parameters measured from corresponding overlay markings on the first and second layers. The operations further include determining a variation of the critical dimensions on the second layer based on the plurality of diffraction parameters.